docs(skills): cite the platform-tool registry instead of restating it (#17259)

The resolution-ladder passage in `skills/objectstack-ai/SKILL.md` carried
three tool counts and two source line ranges. Counts and ranges are copies
of the registry, so every registry change owed this passage a correction
that nobody made: the `validate-ai-tool-references.ts` range was already
wrong before the registry grew, and the counts went stale on the merge that
added tools.

Cite by symbol instead. `collectToolUniverse` names the resolver and
`PLATFORM_TOOLS_BY_PACKAGE` names the registry, both without ranges; the
per-package character of each group stays (structure, not counts) and the
passage keeps telling the reader to open the file for the exact set. Nothing
in the tree read the removed numbers, so no gate or generator follows.

Claude-Session: https://claude.ai/code/session_01MoTv7pn338AZ71owsp19gQ

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

Author: os-justin

skills/objectstack-ai/SKILL.md

@@ -68,17 +68,16 @@ conditions.
 ### Naming the tools: the resolution ladder
 
 A `skill.tools[]` entry resolves against the union of three sources
-(`packages/lint/src/validate-ai-tool-references.ts:148-171`):
+(`collectToolUniverse` in `packages/lint/src/validate-ai-tool-references.ts`):
 
 1. **`stack.tools[].name`** — records your own stack declares. ADR-0109: the
    default third-party path declares **none** (see *Tool metadata* below).
-2. **`PLATFORM_PROVIDED_TOOL_NAMES`** — the 30 statically-registered platform
-   tools, grouped by owning package in
-   `packages/spec/src/system/constants/platform-tool-names.ts:38-82` — 6 data /
-   knowledge tools from `service-ai` (`query_records`, `get_record`,
-   `query_data`, `aggregate_data`, `search_knowledge`, `visualize_data`) and 24
-   schema / metadata / package tools from `service-ai-studio`. Read that file for
-   the exact set: it is the registry the lint rule checks against.
+2. **`PLATFORM_PROVIDED_TOOL_NAMES`** — the statically-registered platform
+   tools, flattened from `PLATFORM_TOOLS_BY_PACKAGE` in
+   `packages/spec/src/system/constants/platform-tool-names.ts`: data /
+   knowledge tools from `service-ai`, schema / metadata / package tools from
+   `service-ai-studio`. Read that file for the exact set: it is the registry
+   the lint rule checks against.
 3. **`action_<name>`** — one tool per AI-exposed Action of your own stack
    (`PLATFORM_TOOL_FAMILY_PREFIXES`). **The default path** for anything your app
    does.