fix(#2071): extract install-time effort resolvers so effort sync stops requiring the un-shipped bin/install.js

`gsd-tools effort sync` crashed in every installed runtime (e.g. ~/.claude/gsd-core/)
with `Cannot find module '../../../bin/install.js'`: cmdEffortSync (src/commands.cts)
required the package-root bin/install.js for its install-time effort resolvers, but the
installer only copies the gsd-core/ subtree into a runtime home — bin/install.js is never
present there. So `effort` config changes silently never reached installed agents without
a full reinstall (exactly the gap #488 was meant to close). 4th instance of the recurring
"runtime code under gsd-core/ requires a file outside the shipped subtree via ../../../"
anti-pattern (#1223/#1920/#1383 were the prior three, all already mitigated).

Fix (ADR-457 direction — extract, single source): move readGsdEffectiveEffortConfig +
resolveInstallTimeEffort (with their _getGsdEffortCatalog + _readGsdConfigFile helpers)
out of the hand-authored bin/install.js into a new src/install-effort-resolver.cts that
compiles into the shipped gsd-core/bin/lib/install-effort-resolver.cjs. commands.cts now
requires it as a sibling (`./install-effort-resolver.cjs`) — always present in the
installed tree — instead of `../../../bin/install.js`. bin/install.js imports the same four
symbols back from the new module (it still calls them + re-exports them), so there is one
source of truth and no duplication/drift. The lazy manifest read is repointed from the
package-root layout (`.., gsd-core, bin, shared`) to the bin/lib layout (`.., shared`).

Scope note: this is one of four instances of the anti-pattern; the other three are already
shipped/guarded. A build-time guard rejecting new cross-boundary requires whose target isn't
in the installer copy manifest (to prevent instance #5) is recommended on the issue but kept
out of this fix.

Tests: tests/effort-sync-installed-runtime.test.cjs does a real minimal install into a temp
home (the golden-parity helper) and runs the issue's exact repro
(`gsd-tools effort sync --config-dir <temp>`), asserting no MODULE_NOT_FOUND for
bin/install.js. Fail-first verified: against pristine next the same test throws
`Cannot find module '../../../bin/install.js'` at cmdEffortSync; post-fix it syncs cleanly.

New module registered in .gitignore (ADR-457), eslint ignores, docs/INVENTORY.md +
INVENTORY-MANIFEST.json. bin/install.js is not shipped and the new module is under bin/lib
(excluded from golden parity), so no golden fixtures change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/INVENTORY-MANIFEST.json

@@ -356,6 +356,7 @@
       "host-integration.cjs",
       "init-command-router.cjs",
       "init.cjs",
+      "install-effort-resolver.cjs",
       "install-engine.cjs",
       "install-profiles.cjs",
       "installer-migration-authoring.cjs",

docs/INVENTORY.md

@@ -451,6 +451,7 @@ Full listing: `gsd-core/bin/lib/*.cjs`.
 | `host-integration.cjs` | Host-Integration Interface (ADR-1239 Phase A) — negotiated capability contract over the six host-integration points; `negotiateHostCapabilities` fail-closes on undeclared/unknown/`undocumented` values, typed degradation ladder, host-capability profiles; the 8 `runtime.hostIntegration` axes are validated in `capability-validator.cjs` and sourced per-CLI in `docs/reference/host-integration-capability-matrix.md` |
 | `init-command-router.cjs` | Thin CJS subcommand router adapter for `gsd-tools init` |
 | `init.cjs` | Compound context loading for each workflow type |
+| `install-effort-resolver.cjs` | Install-time effort resolution — `readGsdEffectiveEffortConfig` (merges `~/.gsd/defaults.json` + project `.planning/config.json`) + `resolveInstallTimeEffort`, extracted from `bin/install.js` (#2071) so `gsd-tools effort sync` can require it from the shipped runtime instead of the never-copied package-root installer; install.js imports them back (single source) |
 | `install-engine.cjs` | Runtime-artifact install engine — `installRuntimeArtifacts`/`uninstallRuntimeArtifacts`/`installOpencodeFamilySkills` + their helpers, extracted from `bin/install.js` (ADR-1239 Phase B, #1679); install.js imports them back and injects `getCommitAttribution` |
 | `install-profiles.cjs` | Install profile allowlist + skill staging for `--minimal` install (#2762); single source of truth for which `gsd-*` skills/agents land in runtime config dirs |
 | `installer-migration-authoring.cjs` | Installer migration authoring guardrails for record metadata, explicit scopes, ownership evidence, and runtime contract citations |