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

src/__init__.py

@@ -18,6 +18,7 @@ from .agent_types import AgentPermissions, AgentRunResult, AgentRuntimeConfig, M
 from .background_runtime import BackgroundSessionRuntime
 from .commands import PORTED_COMMANDS, build_command_backlog
 from .config_runtime import ConfigMutation, ConfigRuntime
+from .lsp_runtime import LSPCallEdge, LSPDiagnostic, LSPReference, LSPRuntime, LSPSymbol
 from .mcp_runtime import MCPRuntime, MCPResource, MCPServerProfile, MCPTool
 from .parity_audit import ParityAuditResult, run_parity_audit
 from .plan_runtime import PlanRuntime, PlanStep
@@ -32,6 +33,7 @@ from .system_init import build_system_init_message
 from .task import PortingTask
 from .task_runtime import TaskRuntime
 from .team_runtime import TeamDefinition, TeamMessage, TeamRuntime
+from .token_budget import TokenBudgetSnapshot, calculate_token_budget, estimate_chat_overhead, format_token_budget
 from .tokenizer_runtime import TokenCounterInfo, clear_token_counter_cache, count_tokens, describe_token_counter
 from .workflow_runtime import WorkflowDefinition, WorkflowRunRecord, WorkflowRuntime
 from .worktree_runtime import WorktreeRuntime, WorktreeSessionState, WorktreeStatusReport
@@ -54,6 +56,11 @@ __all__ = [
     'BackgroundSessionRuntime',
     'ConfigMutation',
     'ConfigRuntime',
+    'LSPCallEdge',
+    'LSPDiagnostic',
+    'LSPReference',
+    'LSPRuntime',
+    'LSPSymbol',
     'LocalCodingAgent',
     'MCPResource',
     'MCPRuntime',
@@ -82,6 +89,7 @@ __all__ = [
     'TeamDefinition',
     'TeamMessage',
     'TeamRuntime',
+    'TokenBudgetSnapshot',
     'TokenCounterInfo',
     'TurnResult',
     'WorkflowDefinition',
@@ -101,9 +109,12 @@ __all__ = [
     'clear_context_caches',
     'clear_token_counter_cache',
     'count_tokens',
+    'calculate_token_budget',
     'default_tool_registry',
     'describe_token_counter',
+    'estimate_chat_overhead',
     'execute_tool',
+    'format_token_budget',
     'get_system_context',
     'get_user_context',
     'load_session',