DSL parser, async DB worker, types, history, metadata, polish

Track 1 implementation plus polish round.

Parser (chumsky):
- Grammar-based DSL producing a typed Command AST.
- create table X with pk [name:type[,name:type...]] supports
  arbitrary names, any user type, compound PKs natively. Bare
  form errors with a friendly hint pointing at `with pk`.
- add column to table X: Name (type); drop table X.
- Required clauses use keyword grammar; -- reserved for opt-in
  flags (ADR-0009). Custom Rich reasons preferred when surfacing
  chumsky errors so unknown-type messages list valid alternatives.

Database (ADR-0010, ADR-0012):
- rusqlite + STRICT tables + foreign_keys=ON.
- Dedicated worker thread; mpsc Request inbox, oneshot replies.
- Typed DbError with friendly_message() hook for H1.
- Internal __rdbms_playground_columns metadata table preserves
  user-facing types across schema reads, atomically maintained
  alongside DDL via Connection transactions. list_tables hides
  it via the new __rdbms_ internal-table convention.

Types (ADR-0005, ADR-0011):
- All ten user-facing types: text, int, real, decimal, bool,
  date, datetime, blob, serial, shortid.
- Type::fk_target_type() for FK-side column-type rule
  (Serial->Int, ShortId->Text, others identity) -- foundation
  for the FK iteration.

App / Runtime / UI:
- update() stays pure-sync; runtime dispatches DSL via spawned
  tasks, results post back as AppEvent::Dsl*.
- Items panel renders live tables list; output panel shows the
  user-facing structure of the current table after each DDL.
- In-memory command history (Up/Down, draft preservation,
  consecutive-duplicate dedup) -- I2 partial.
- Mouse capture removed; terminal native text selection
  restored (toggle approach revisited when scroll/click
  features land).

Docs:
- ADRs 0009 (DSL syntax conventions), 0010 (DB worker),
  0011 (FK type compat), 0012 (internal metadata table).
- requirements.md progress notes; new V4 entry for the
  scrollable session-log + inline rich rendering + Markdown
  export direction.

Tests: 103 passing (91 lib + 12 integration), 0 skipped.
Clippy clean with nursery enabled.

Cargo.lock

@@ -23,6 +23,15 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "ar_archive_writer"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7eb93bbb63b9c227414f6eb3a0adfddca591a8ce1e9b60661bb08969b87e340b"
+dependencies = [
+ "object",
+]
+
 [[package]]
 name = "atomic"
 version = "0.6.1"
@@ -107,6 +116,16 @@ dependencies = [
  "rustversion",
 ]
 
+[[package]]
+name = "cc"
+version = "1.2.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d16d90359e986641506914ba71350897565610e87ce0ad9e6f28569db3dd5c6d"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.4"
@@ -119,6 +138,20 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 
+[[package]]
+name = "chumsky"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0d2bfadce76f963d776feff99db6dc33783829539258314776383b33e2a00f8"
+dependencies = [
+ "hashbrown 0.15.5",
+ "regex-automata",
+ "serde",
+ "stacker",
+ "unicode-ident",
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "compact_str"
 version = "0.9.0"
@@ -343,6 +376,18 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "fallible-iterator"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2acce4a10f12dc2fb14a218589d4f1f62ef011b2d0cc4b3cb1bba8e94da14649"
+
+[[package]]
+name = "fallible-streaming-iterator"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7360491ce676a36bf9bb3c56c1aa791658183a54d2744120f27285738d90465a"
+
 [[package]]
 name = "fancy-regex"
 version = "0.11.0"
@@ -370,6 +415,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+
 [[package]]
 name = "finl_unicode"
 version = "1.4.0"
@@ -477,6 +528,8 @@ version = "0.15.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
 dependencies = [
+ "allocator-api2",
+ "equivalent",
  "foldhash 0.1.5",
 ]
 
@@ -497,6 +550,15 @@ version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4f467dd6dccf739c208452f8014c75c18bb8301b050ad1cfb27153803edb0f51"
 
+[[package]]
+name = "hashlink"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea0b22561a9c04a7cb1a302c013e0259cd3b4bb619f145b32f72b8b4bcbed230"
+dependencies = [
+ "hashbrown 0.16.1",
+]
+
 [[package]]
 name = "heck"
 version = "0.5.0"
@@ -630,6 +692,17 @@ version = "0.2.186"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
 
+[[package]]
+name = "libsqlite3-sys"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1f111c8c41e7c61a49cd34e44c7619462967221a6443b0ec299e0ac30cfb9b1"
+dependencies = [
+ "cc",
+ "pkg-config",
+ "vcpkg",
+]
+
 [[package]]
 name = "line-clipping"
 version = "0.3.7"
@@ -800,6 +873,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "object"
+version = "0.37.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff76201f031d8863c38aa7f905eca4f53abbfa15f609db4277d44cd8938f33fe"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -939,6 +1021,12 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
 
+[[package]]
+name = "pkg-config"
+version = "0.3.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19f132c84eca552bf34cab8ec81f1c1dcc229b811638f9d283dceabe58c5569e"
+
 [[package]]
 name = "portable-atomic"
 version = "1.13.1"
@@ -980,6 +1068,16 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "psm"
+version = "0.1.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "645dbe486e346d9b5de3ef16ede18c26e6c70ad97418f4874b8b1889d6e761ea"
+dependencies = [
+ "ar_archive_writer",
+ "cc",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.45"
@@ -1106,11 +1204,13 @@ name = "rdbms-playground"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "chumsky",
  "crossterm",
  "futures-util",
  "insta",
  "pretty_assertions",
  "ratatui",
+ "rusqlite",
  "thiserror 2.0.18",
  "tokio",
  "tracing",
@@ -1155,6 +1255,31 @@ version = "0.8.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
+[[package]]
+name = "rsqlite-vfs"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8a1f2315036ef6b1fbacd1972e8ee7688030b0a2121edfc2a6550febd41574d"
+dependencies = [
+ "hashbrown 0.16.1",
+ "thiserror 2.0.18",
+]
+
+[[package]]
+name = "rusqlite"
+version = "0.39.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a0d2b0146dd9661bf67bb107c0bb2a55064d556eeb3fc314151b957f313bcd4e"
+dependencies = [
+ "bitflags 2.11.1",
+ "fallible-iterator",
+ "fallible-streaming-iterator",
+ "hashlink",
+ "libsqlite3-sys",
+ "smallvec",
+ "sqlite-wasm-rs",
+]
+
 [[package]]
 name = "rustc_version"
 version = "0.4.1"
@@ -1264,6 +1389,12 @@ dependencies = [
  "lazy_static",
 ]
 
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
 [[package]]
 name = "signal-hook"
 version = "0.3.18"
@@ -1329,6 +1460,31 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "sqlite-wasm-rs"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b2c760607300407ddeaee518acf28c795661b7108c75421303dbefb237d3a36"
+dependencies = [
+ "cc",
+ "js-sys",
+ "rsqlite-vfs",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "stacker"
+version = "0.1.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "640c8cdd92b6b12f5bcb1803ca3bbf5ab96e5e6b6b96b9ab77dabe9e880b3190"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "libc",
+ "psm",
+ "windows-sys",
+]
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -1690,6 +1846,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
 
+[[package]]
+name = "vcpkg"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "accd4ea62f7bb7a82fe23066fb0957d48ef677f6eeb8215f372f52e48bb32426"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"