Implemented the next parity slice: prompt-budget preflight and context collapse.

Core changes:

  - Added claw-code/src/token_budget.py for projected prompt size, chat-framing overhead, output reserve, and soft/hard input limits.
  - Wired preflight prompt-length validation and auto-compact/context collapse into claw-code/src/agent_runtime.py.
  - Extended claw-code/src/compact.py so compaction reports usage back to the runtime.
  - Added inspection surfaces in claw-code/src/agent_slash_commands.py and claw-code/src/main.py:
      - /token-budget and /budget
      - token-budget
  - Hardened claw-code/src/tokenizer_runtime.py so arbitrary simple model names fall back cleanly instead of trying a slow Transformers
    lookup.
  - Exported the new helpers in claw-code/src/__init__.py.

  Docs and tracking:

  - Updated claw-code/PARITY_CHECKLIST.md to mark prompt-length validation, token-budget calculation, and auto-compact/context collapse as
    done.
  - Updated claw-code/README.md and claw-code/TESTING_GUIDE.md with the new commands and behavior.

  Tests:

  - Added claw-code/tests/test_token_budget.py.
  - Updated claw-code/tests/test_agent_runtime.py, claw-code/tests/test_agent_slash_commands.py, claw-code/tests/test_main.py, and claw-code/
    tests/test_agent_context_usage.py.
  - Verified with:
      - /data/fs201059/aa17626/miniconda3/bin/python3 -m compileall src tests
      - /data/fs201059/aa17626/miniconda3/bin/python3 -m unittest -v tests.test_token_budget
        tests.test_agent_runtime.AgentRuntimeTests.test_agent_rejects_prompt_before_backend_when_preflight_input_budget_is_exceeded
        tests.test_agent_runtime.AgentRuntimeTests.test_agent_auto_compacts_context_before_next_model_call tests.test_agent_slash_commands
        tests.test_main tests.test_compact tests.test_tokenizer_runtime tests.test_agent_context_usage
      - Result: 71 tests, OK

tests/test_lsp_runtime.py

@@ -0,0 +1,74 @@
+from __future__ import annotations
+
+import tempfile
+import unittest
+from pathlib import Path
+
+from src.lsp_runtime import LSPRuntime
+
+
+SAMPLE_SOURCE = '''def helper(value):
+    """Double a numeric value."""
+    return value * 2
+
+
+def orchestrate(item):
+    return helper(item)
+
+
+class Greeter:
+    def greet(self, name):
+        return helper(len(name))
+'''
+
+
+class LSPRuntimeTests(unittest.TestCase):
+    def test_runtime_renders_symbols_definitions_references_and_hover(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp_dir:
+            workspace = Path(tmp_dir)
+            (workspace / 'sample.py').write_text(SAMPLE_SOURCE, encoding='utf-8')
+            runtime = LSPRuntime.from_workspace(workspace)
+
+            summary = runtime.render_summary()
+            symbols = runtime.render_document_symbols('sample.py')
+            workspace_symbols = runtime.render_workspace_symbols('helper')
+            definition = runtime.render_definition('sample.py', 7, 12)
+            references = runtime.render_references('sample.py', 7, 12)
+            hover = runtime.render_hover('sample.py', 1, 5)
+
+        self.assertIn('Indexed candidate files: 1', summary)
+        self.assertIn('# LSP Document Symbols', symbols)
+        self.assertIn('function helper', symbols)
+        self.assertIn('function orchestrate', symbols)
+        self.assertIn('class Greeter', symbols)
+        self.assertIn('# LSP Workspace Symbols', workspace_symbols)
+        self.assertIn('helper', workspace_symbols)
+        self.assertIn('# LSP Definition', definition)
+        self.assertIn('function helper', definition)
+        self.assertIn('# LSP References', references)
+        self.assertIn('helper(item)', references)
+        self.assertIn('# LSP Hover', hover)
+        self.assertIn('signature=helper(value)', hover)
+        self.assertIn('Double a numeric value.', hover)
+
+    def test_runtime_renders_call_hierarchy_and_diagnostics(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp_dir:
+            workspace = Path(tmp_dir)
+            (workspace / 'sample.py').write_text(SAMPLE_SOURCE, encoding='utf-8')
+            (workspace / 'broken.py').write_text('def broken(:\n    pass\n', encoding='utf-8')
+            runtime = LSPRuntime.from_workspace(workspace)
+
+            hierarchy = runtime.render_prepare_call_hierarchy('sample.py', 6, 12)
+            incoming = runtime.render_incoming_calls('sample.py', 1, 5)
+            outgoing = runtime.render_outgoing_calls('sample.py', 6, 12)
+            diagnostics = runtime.render_diagnostics('broken.py')
+
+        self.assertIn('# LSP Call Hierarchy', hierarchy)
+        self.assertIn('symbol=orchestrate', hierarchy)
+        self.assertIn('# LSP Incoming Calls', incoming)
+        self.assertIn('orchestrate', incoming)
+        self.assertIn('greet', incoming)
+        self.assertIn('# LSP Outgoing Calls', outgoing)
+        self.assertIn('helper', outgoing)
+        self.assertIn('# LSP Diagnostics', diagnostics)
+        self.assertIn('syntax-error', diagnostics)