Admin: delegate /.well-known/atproto-did to Atmosphere

[kraftbj]

Summary

• FOSSE's /.well-known/atproto-did handler has been a mirror of Atmosphere's identity contract since the start, and it has now broken twice — once on the original is_connected() gate (404'd during reauth) and again on the follow-up in PR 166. Atmosphere's bundled handler already gates on has_identity(), validates the DID via get_did(), and returns the same text/plain body, so there's no FOSSE-specific behavior worth maintaining a parallel implementation for.
• Delete serve_atproto_did_well_known() and the init priority-1 registration in Bluesky_Provider. Atmosphere now owns the route end-to-end at template_redirect priority 10.
• Keep the template_redirect priority-1 suppression hook so the existing fosse_serve_atproto_did_well_known filter still means "neither plugin responds": when it returns false, the hook clears Atmosphere's atmosphere_wellknown query var and forces a 404.
• Drop the now-dead well-known response tests; keep the suppression-hook tests.
• Update sdd/bluesky-handle-setup/implementation-notes.md to record the delegation decision.

Fixes #169.

Behavior change

No user-facing behavior change for the default-on case. Atmosphere's handler already gates on has_identity(), which is the contract PR 166 made FOSSE adopt; the response shape (200 + DID body, 404 otherwise) is identical. Sites that filter fosse_serve_atproto_did_well_known to false continue to get a 404 from neither plugin.

Test Plan

• ./vendor/bin/phpunit --colors=always --do-not-cache-result tests/php/Admin/Bluesky_ProviderTest.php (96 passing)
• composer run-script lint-php -- src/Admin/class-bluesky-provider.php tests/php/Admin/Bluesky_ProviderTest.php

[Copilot]

Pull request overview

Delegates the /.well-known/atproto-did endpoint fully to the bundled Atmosphere plugin to avoid FOSSE maintaining a parallel handler that can drift from Atmosphere’s identity contract, while preserving FOSSE’s existing opt-out behavior via the fosse_serve_atproto_did_well_known filter.

Changes:

• Removed FOSSE’s init-hooked /.well-known/atproto-did handler and its associated response helper logic.
• Kept (and documented) the template_redirect priority-1 suppression hook so filtering fosse_serve_atproto_did_well_known to false still results in neither plugin serving the route.
• Dropped now-dead PHPUnit coverage for FOSSE’s former response helper and updated SDD implementation notes to record the delegation decision.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Admin/class-bluesky-provider.php	Removes the duplicate well-known handler and positions FOSSE as opt-out-only via the existing suppression hook.
tests/php/Admin/Bluesky_ProviderTest.php	Removes tests tied to the deleted response helper and updates hook-registration assertions accordingly.
sdd/bluesky-handle-setup/implementation-notes.md	Documents that Atmosphere now owns the well-known route and records the rationale for delegation.

Comments suppressed due to low confidence (1)

tests/php/Admin/Bluesky_ProviderTest.php:857

• With FOSSE delegating /.well-known/atproto-did to Atmosphere, the PHPUnit coverage for the actual well-known response behavior (200 vs 404, body shape, malformed DID handling) was removed. Consider adding an integration/E2E-level test that exercises the real HTTP endpoint (or otherwise validates Atmosphere’s handler contract) so future Atmosphere syncs can’t silently change the public response shape without a failing test.

	/**
	 * The suppression hook is a no-op for unrelated atmosphere_wellknown query vars.
	 */
	public function test_maybe_suppress_atmosphere_well_known_no_op_for_other_query_vars() {
		global $wp_query;