docs(bundles): document --integration on bundle update

[jawwad-ali]

Description

specify bundle update accepts an --integration option:

@bundle_app.command("update")
def bundle_update(
    ...
    integration: str = typer.Option(None, "--integration", help="Override integration"),
    offline: bool = typer.Option(False, "--offline", ...),
)

(confirmed by specify bundle update --help). At runtime it is the integration override applied only when the project's active integration can't be detected — active_integration=detected if detected is not None else integration.

But the Update Bundles options table in docs/reference/bundles.md lists only --all and --offline, omitting --integration — even though the install and init tables in the same doc already document it. So a real, working flag is undocumented for update.

Fix

Add the --integration row to the Update Bundles options table, describing its update-time semantics (refresh-time override, applied only when the active integration can't be determined). Docs-only change; the source is the source-of-truth.

Testing

• specify bundle update --help lists --integration (the flag the doc now documents).
• npx markdownlint-cli2 docs/reference/bundles.md → 0 errors.

AI Disclosure

• I did use AI assistance (describe below)

Found and fixed with Claude Code (Claude Opus 4.8) under my direction. AI diffed the update command's accepted options against the doc table; I confirmed the flag via --help and the signature, wrote the row to match its runtime semantics, ran markdownlint, and reviewed the diff before submitting.

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