docs: sync README bridge-state path to new namespace (#199)

Author: kiki830621

plugins/issue-driven-dev/README.md

@@ -89,8 +89,8 @@ GitHub mentions are an irreversible side effect; the rule is mandatory not advis
 
 When `spectra-discuss` is interrupted mid-flow to invoke an IDD skill (e.g. "let me capture this finding to the issue"), the bridge protocol preserves and resumes context:
 
-- **Step 0.7 Detect** — `--resume-spectra="<topic>"` flag, `--source` contains `spectra-discuss`, `spectra list --json` shows in-flight changes, or `.claude/state/idd-bridge.json` exists → `SPECTRA_BRIDGE_ACTIVE=1`
-- **Step N-1 Bookmark** — `.claude/state/idd-bridge.json` written with verbatim `spectra_topic` + `issue_url` + `open_questions[]` + `idd_action_url` + `next_step_hint`
+- **Step 0.7 Detect** — `--resume-spectra="<topic>"` flag, `--source` contains `spectra-discuss`, `spectra list --json` shows in-flight changes, or `.claude/.idd/state/bridge.json` exists (legacy fallback: `.claude/state/idd-bridge.json`) → `SPECTRA_BRIDGE_ACTIVE=1`
+- **Step N-1 Bookmark** — `.claude/.idd/state/bridge.json` written with verbatim `spectra_topic` + `issue_url` + `open_questions[]` + `idd_action_url` + `next_step_hint`
 - **Step N Resume Prompt** — final output prints a clearly-delimited `↩ Resume spectra-discuss` block with a copy-pasteable `/spectra-discuss <topic>...` prompt
 
 Hard rules: never auto-invoke `/spectra-discuss` (user controls pacing); never paraphrase `spectra_topic`; resume prompt is the actual recovery — bookmark file is convenience.