fix(dynamic): send booleans the caller set to false instead of dropping them

[nictuku]

The bug

Dynamic commands only forwarded a boolean when it was true:

for propName, val := range boolFlags {
    if val != nil && *val { toolArgs[propName] = true }
}

Cobra parses --flag=false and records it as Changed, but the value was then discarded — so an explicit false was byte-identical to omitting the flag. false could not be transmitted at all, which means any tool parameter whose server-side default is true was permanently stuck on.

I hit this validating pipeboard.co#2242: pipeboard meta-ads delete-catalog-products --dry-run=false came back dry_run: true, and a deliberately wrong --expected-count produced a warning instead of a rejection — both dry-run tells. The tool could not be executed through a dynamic command at all.

Blast radius

15 tool/flag pairs across the cached Meta and Google schemas declare a true default. They failed in both directions:

Failure	Tools
Fail-safe — operation impossible	delete_catalog_products --dry-run, --readback
Fail-UNSAFE — caller asks for a draft, gets a live object	publish_facebook_page_post --published=false, create_collection_ad --is-published=false, create_instant_experience --is-published=false
Cannot opt out of a network	create_google_ads_campaign --target-youtube=false, --target-google-search=false

The unsafe row is the reason this is worth shipping promptly: someone creating a deliberately unpublished post got a live one, with no error.

The fix

Key off cmd.Flags().Changed() and forward the parsed value. An unset boolean is still omitted, so server-side defaults keep applying — only explicitly-typed flags are now sent.

Both flag registration and the change lookup go through a new propNameToFlagName, so the underscore→hyphen mapping can't drift between them (that mismatch would silently drop every boolean again).

Argument building is extracted into buildToolArgs and flag registration into registerToolFlags, so the behavior is unit-testable without network I/O. No behavior change for strings, numbers, arrays, or objects.

Note: a matching quirk remains for string flags — if *val == "" { continue } means an explicit empty string can't be sent either. Left alone deliberately: unlike booleans it has no "default is non-empty" failure mode, and changing it would alter behavior for scripts that pass a possibly-empty shell variable expecting omission.

Tests

TestBuildToolArgsBooleans (5 cases), TestBuildToolArgsHyphenatedBooleanFlag, TestBuildToolArgsTypeCoercion. They drive real cobra parsing through the real code path.

Verified they actually catch the bug: reverting just the fix hunk makes 3 of them fail —

--- FAIL: TestBuildToolArgsBooleans/explicit_false_is_sent,_not_dropped
    got map[catalog_id:123], want map[catalog_id:123 dry_run:false]
--- FAIL: TestBuildToolArgsHyphenatedBooleanFlag
    is_published = <nil> (present=false), want false

go build, go vet, gofmt, go test ./... all clean.

End-to-end verification

Against a local Next dev server + Python MCP backend, on a Pipeboard-owned ad account, using a disposable [PIPEBOARD TEST] catalog with one product:

Binary	Invocation	Result
0.8.0	--dry-run=false --expected-count 1	dry_run: true, deleted: 0 — bug reproduced
fixed	(no --dry-run)	dry_run: true, deleted: 0 — default preserved
fixed	--dry-run=false --expected-count 7	hard rejection, nothing deleted
fixed	--dry-run=false --expected-count 1	dry_run: false, deleted: 1, readback confirmed_absent: 1, still_present: []

Test catalog deleted afterwards; the account's own pre-existing catalog was only ever read and still hashes to the manifest token recorded before the run.