dotcli: Add dot kde save with schema-backed defaults and completion.

Introduces the dot kde subcommand family (fish dispatcher plus a Python
helper under commands/kde/), a flat identifier=value manifest, and
dot kde save in both its explicit-identifier and no-argument refresh
modes. Settings resolve to KDE's KConfigXT schema-backed mechanism via a
(rcfile -> [kcfg files]) mapping table auto-derived by scanning the
system schema directory (overridable via DOT_KDE_KCFG_DIR), plus a
hand-maintained exceptions list for schemas that only declare their
target rc file at runtime. Also wires tab-completion for dot kde save
identifiers, sourced live from that same mapping table.

.config/dot/.claude/tasks/0001-kde-schema-backed-save.md

@@ -42,12 +42,22 @@ Add README rows for `dot kde help`, `dot kde save <identifier>`, and
 
 ## Acceptance criteria
 
-- [ ] `dot kde` and `dot kde save` are discoverable via `dot help` and dispatch correctly
-- [ ] Manifest parsing splits correctly on the first `=` (values may contain `=`) and the first two `.`s of the identifier (keys may contain dots/spaces)
-- [ ] The `(rcfile → [kcfg files])` mapping table is derived by scanning a schema directory for `<kcfgfile name="...">`, plus the hand-maintained exceptions list for `arg="true">` schemas
-- [ ] The schema directory is overridable via an environment variable, defaulting to the real system path
-- [ ] `dot kde save <identifier>` reads the current live value via `kreadconfig6` and adds a new declared entry to the manifest
-- [ ] `dot kde save` with no arguments refreshes every already-declared manifest entry's stored value from the live system, leaving undeclared settings untouched
-- [ ] `dot kde help` and `dot kde save help` print usage without touching the manifest or invoking `kreadconfig6`/`kwriteconfig6`
-- [ ] Tests run against a scratch `$HOME` and a fixture `.kcfg` schema directory, exercising manifest read/write, identifier parsing, and mapping-table-driven default lookup, per the project's scratch-`$HOME`-plus-`fishtape` convention
-- [ ] README has rows for `dot kde help`, `dot kde save <identifier>`, and `dot kde save`
+- [x] `dot kde` and `dot kde save` are discoverable via `dot help` and dispatch correctly
+- [x] Manifest parsing splits correctly on the first `=` (values may contain `=`) and the first two `.`s of the identifier (keys may contain dots/spaces)
+- [x] The `(rcfile → [kcfg files])` mapping table is derived by scanning a schema directory for `<kcfgfile name="...">`, plus the hand-maintained exceptions list for `arg="true">` schemas
+- [x] The schema directory is overridable via an environment variable, defaulting to the real system path
+- [x] `dot kde save <identifier>` reads the current live value via `kreadconfig6` and adds a new declared entry to the manifest
+- [x] `dot kde save` with no arguments refreshes every already-declared manifest entry's stored value from the live system, leaving undeclared settings untouched
+- [x] `dot kde help` and `dot kde save help` print usage without touching the manifest or invoking `kreadconfig6`/`kwriteconfig6`
+- [x] Tests run against a scratch `$HOME` and a fixture `.kcfg` schema directory, exercising manifest read/write, identifier parsing, and mapping-table-driven default lookup, per the project's scratch-`$HOME`-plus-`fishtape` convention
+- [x] README has rows for `dot kde help`, `dot kde save <identifier>`, and `dot kde save`
+
+## Implementation Notes
+
+- File layout: `commands/kde/kde.fish` (thin dispatcher: help-before-dispatch at the `dot kde` level, then hands off to the Python helper) plus `commands/kde/kde.py` (manifest parsing, mapping-table derivation, mechanism resolution, `kreadconfig6` invocation, and `save`'s own help-before-work check).
+- Manifest location: `~/.config/dot/kde-manifest`, a flat file directly under `~/.config/dot/` as specified.
+- Mechanism dispatch (`resolve_mechanism`) implements all three branches described in the parent spec (shortcuts / schema / freeform) even though only `schema` is wired to real behavior; `shortcuts` and `freeform` both currently raise a clear "not yet supported" error from `save_one`, so later tasks can fill them in without restructuring the dispatch.
+- Test fixtures added under `tests/fixtures/kcfg/`: `testrc.kcfg` (a plain `<kcfgfile name="...">` schema, including an entry whose ini `key=` differs from its schema `name=`, and one entry whose key contains dots and spaces), `kwin.kcfg` (an `arg="true"` schema resolved only via the hand-maintained exceptions list), and `unmapped.kcfg` (an `arg="true"` schema absent from that list, proving it's never guessed at from its own filename).
+- Per the project's testing convention, `kreadconfig6` is never mocked for the tests exercising actual `save` behavior — it runs for real against fixture rc files under a scratch `$HOME`. It's faked (via a `$PATH`-prepended logging stub) only for the two tests asserting that `dot kde help` / `dot kde save help` never invoke it.
+- Applied two small cleanups surfaced by `/review-uncommitted`'s Standards pass before closing out: extracted a shared `_parse_kcfg` helper (was duplicated between `build_kcfg_map` and `find_schema_default`), and introduced a `Setting = namedtuple("Setting", ["file", "group", "key"])` to stop threading those three strings as separate parameters across `resolve_mechanism`/`find_schema_default`/`read_live_value`/`save_one`.
+- The Spec pass caught that the `unmapped.kcfg` fixture was created but never actually exercised by a test; added a case asserting `dot kde save unmapped.Whatever.Setting` resolves to freeform rather than schema-backed.