feat(#1213): Capability State Writer — write-side inverse of the resolver (#1225)

* feat(#1213): Capability State Writer — write-side inverse of the resolver

Adds src/capability-writer.cts (setCapabilityState + cmdCapabilitySet) and the
`gsd-tools capability set` subcommand: the write-side inverse of the capability
resolver (ADR-1213). One desired capability state projects onto the substrates —
`enabled` drives the runtime surface (canonical on/off), `gates` drive federated
config keys (hook granularity), install profile is a read-only floor — then
re-resolves and reports divergence (assert-and-report), so "off means off" holds
as a write-time invariant. Adds batched setConfigValues; routes gsd:settings
capability hook-gates through the writer. Docs: CLI-TOOLS reference, how-to,
ADR-1213, CONTEXT.md term.

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

* chore(#1213): add changeset for Capability State Writer (#1225)

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

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/workflow-size-baseline.json

@@ -68,7 +68,7 @@
   "session-report.md": 4044,
   "settings-advanced.md": 39621,
   "settings-integrations.md": 15801,
-  "settings.md": 32133,
+  "settings.md": 33413,
   "ship.md": 24388,
   "sketch-wrap-up.md": 14223,
   "sketch.md": 19960,