#8473: fix(gateway): prevent spurious restarts on meta.lastTouchedAt changes

## Problem Config reload watcher triggers gateway restart when `meta.lastTouchedAt` updates, even though the `meta` block contains no actionable config changes. This causes: - Unnecessary gateway restarts on every config write - AbortError noise in logs - Potential disruption during high-activity periods ## Solution Add `meta` prefix to `BASE_RELOAD_RULES_TAIL` with `kind: 'none'`: ```typescript { prefix: 'meta', kind: 'none' }, ``` This follows the existing pattern for `identity`, `wizard`, and other non-actionable config sections. ## Verification Local testing confirmed stable — gateway PID unchanged after config writes that only update `meta.lastTouchedAt`. Fixes #8442 <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This change updates the gateway config reload rules to treat the top-level `meta` config section as non-actionable by adding `{ prefix: "meta", kind: "none" }` to `BASE_RELOAD_RULES_TAIL` in `src/gateway/config-reload.ts`. This prevents the reload planner from scheduling hot reloads or full gateway restarts when only `meta.lastTouchedAt` (or other `meta.*` fields) changes, aligning `meta` with other explicitly ignored sections like `identity` and `wizard`. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is a one-line addition to an existing no-op prefix list; it only suppresses reload actions for `meta.*` changes and does not affect matching logic for other prefixes. - No files require special attention <!-- greptile_other_comments_section --> _{(4/5) You can add custom instructions or style guidelines for the agent [here](https://app.greptile.com/review/github)!} <!-- /greptile_comment -->