feat(m7.5a): TypeScript progressive disclosure + conformance parity

[shamspias]

The cross-language parity gate: the full shared conformance suite now passes in TypeScript, mirroring Python and Go.

• disclosure.ts: dual progressive disclosure (§2.12) — above 12 registered capabilities the model sees only a constant-size search_capabilities tool instead of the whole registry; matches are exposed and become directly callable. A SchemaIndex, when attached, is reachable only via search_schema. Keyword tokenize/score, exposed-match tracking, and a collision guard, all mirroring the Python and Go ports so the base-context behavior is language-neutral.
• loop.ts: discovery calls are answered inline — harness-internal reads that are never gated and allowed under ask(); the model.complete tool surface now comes from Disclosure.tools(). Agent config and RunOptions gain schema/defer.
• tests/conformance.test.ts: the TS adapter for spec/conformance/cases — loads the same language-neutral YAML (js-yaml, a test-only dep), drives the TS harness with a scripted FakeModel, and asserts each case's expect block. Passes all 13 neutral cases (linter + golden), skipping only the {program} code-mode case, whose step carries Python source (a language-specific dialect, contract §7.5) — TS code-mode will be validated by native tests.
• disclosure.test.ts: deferral threshold, search exposing matches, schema search, empty-query and no-match hints, and the discovery-tool name collision.
• README/roadmap: TypeScript now listed as passing the shared conformance suite.

Verified: make js-check green — format, typecheck, 111 tests (110 pass, 1 skip).