Add CLAUDE.md with versioned changelog, update README

- Created CLAUDE.md with instructions to update changelog and README on
  every commit, version number (v1.2.0), and full changelog from v1.0.0
- Updated README: document-scope BLIGHT:: syntax, processing order,
  two-line failure format, complete_document() in AI provider section

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -2,7 +2,7 @@
 
 A module in the **BLIGHT** ecosystem.
 
-BLIGHT: CUE monitors Gitea repositories containing markdown files. When a push is received, it scans changed files for `BLIGHT:` trigger lines, sends the surrounding document to an AI model along with the instruction, and writes the result back to the file in-place — fully automated.
+BLIGHT: CUE monitors Gitea repositories containing markdown files. When a push is received, it scans changed files for `BLIGHT:` trigger lines, sends the document to an AI model along with the instruction, and writes the result back to the file in-place — fully automated.
 
 ---
 
@@ -10,16 +10,25 @@ BLIGHT: CUE monitors Gitea repositories containing markdown files. When a push i
 
 1. You write a `BLIGHT:` trigger anywhere in a markdown file and push it to Gitea.
 2. Gitea sends a webhook POST to this server.
-3. The server fetches the file, finds all `BLIGHT:` triggers, and processes them one by one.
-4. Each trigger is replaced with the AI's response at the exact position of the trigger line.
-5. The updated file is committed back to the repo automatically.
+3. The server fetches the file, finds all `BLIGHT:` triggers, and processes them.
+4. Each trigger is replaced with the AI's response, then the updated file is committed back automatically.
 
 ### Trigger Syntax
 
+Triggers are case-insensitive — `BLIGHT:`, `blight:`, `Blight::`, etc. all work.
+
+**Inline trigger** — replaces only the trigger line with the AI's response:
+
 ```
 BLIGHT: <your instruction here>
 ```
 
+**Document-scope trigger** — replaces the entire file with the AI's rewritten version:
+
+```
+BLIGHT:: <your instruction here>
+```
+
 Examples:
 
 ```markdown
@@ -31,22 +40,30 @@ BLIGHT: Explain the key differences between は and が based on the paragraph a
 ```
 
 ```markdown
-BLIGHT: Spell check this entire document and list any errors found.
+BLIGHT: Write a conclusion paragraph for this document.
 ```
 
 ```markdown
-BLIGHT: Write a conclusion paragraph for this document.
+BLIGHT:: Spellcheck and lightly reformat this entire document.
 ```
 
+### Processing Order
+
+When a file contains multiple triggers:
+
+1. All inline (`BLIGHT:`) triggers are processed first, in document order.
+2. All document-scope (`BLIGHT::`) triggers are processed next, in document order — each one operates on the result of the previous.
+
 ### Failure Behavior
 
 If the AI call fails after 3 attempts, the trigger is replaced with:
 
 ```html
 <!-- BLIGHT_FAILED: your original instruction -->
+<!-- BLIGHT_ERROR: <error message> -->
 ```
 
-You can re-trigger processing by editing the file to restore the original `BLIGHT:` line and pushing again.
+You can re-trigger processing by editing the file to restore the original trigger line and pushing again.
 
 ---
 
@@ -224,12 +241,17 @@ from abc import ABC, abstractmethod
 
 class AIProvider(ABC):
     def complete(self, document: str, instruction: str) -> str:
+        """Return text to insert in place of an inline BLIGHT: trigger."""
+        ...
+
+    def complete_document(self, document: str, instruction: str) -> str:
+        """Return the full rewritten document for a BLIGHT:: trigger."""
         ...
 ```
 
 To add a new provider (e.g. OpenRouter):
 
-1. Create `ai/openrouter.py` and implement `AIProvider`.
+1. Create `ai/openrouter.py` and implement both methods of `AIProvider`.
 2. In `processor.py`, replace `GeminiProvider()` with your new class.
 
 ---