Rename all arch references to plano (#745)

* Rename all arch references to plano across the codebase

Complete rebrand from "Arch"/"archgw" to "Plano" including:
- Config files: arch_config_schema.yaml, workflow, demo configs
- Environment variables: ARCH_CONFIG_* → PLANO_CONFIG_*
- Python CLI: variables, functions, file paths, docker mounts
- Rust crates: config paths, log messages, metadata keys
- Docker/build: Dockerfile, supervisord, .dockerignore, .gitignore
- Docker Compose: volume mounts and env vars across all demos/tests
- GitHub workflows: job/step names
- Shell scripts: log messages
- Demos: Python code, READMEs, VS Code configs, Grafana dashboard
- Docs: RST includes, code comments, config references
- Package metadata: package.json, pyproject.toml, uv.lock

External URLs (docs.archgw.com, github.com/katanemo/archgw) left as-is.

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

* Update remaining arch references in docs

- Rename RST cross-reference labels: arch_access_logging, arch_overview_tracing, arch_overview_threading → plano_*
- Update label references in request_lifecycle.rst
- Rename arch_config_state_storage_example.yaml → plano_config_state_storage_example.yaml
- Update config YAML comments: "Arch creates/uses" → "Plano creates/uses"
- Update "the Arch gateway" → "the Plano gateway" in configuration_reference.rst
- Update arch_config_schema.yaml reference in provider_models.py
- Rename arch_agent_router → plano_agent_router in config example

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

* Fix remaining arch references found in second pass

- config/docker-compose.dev.yaml: ARCH_CONFIG_FILE → PLANO_CONFIG_FILE,
  arch_config.yaml → plano_config.yaml, archgw_logs → plano_logs
- config/test_passthrough.yaml: container mount path
- tests/e2e/docker-compose.yaml: source file path (was still arch_config.yaml)
- cli/planoai/core.py: comment and log message
- crates/brightstaff/src/tracing/constants.rs: doc comment
- tests/{e2e,archgw}/common.py: get_arch_messages → get_plano_messages,
  arch_state/arch_messages variables renamed
- tests/{e2e,archgw}/test_prompt_gateway.py: updated imports and usages
- demos/shared/test_runner/{common,test_demos}.py: same renames
- tests/e2e/test_model_alias_routing.py: docstring
- .dockerignore: archgw_modelserver → plano_modelserver
- demos/use_cases/claude_code_router/pretty_model_resolution.sh: container name

Note: x-arch-* HTTP header values and Rust constant names intentionally
preserved for backwards compatibility with existing deployments.

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

demos/use_cases/model_choice_with_test_harness/README.md

@@ -1,6 +1,6 @@
 # Model Choice Newsletter Demo
 
-This folder demonstrates a practical workflow for rapid model adoption and safe model switching using Arch Gateway (`plano`). It includes both a minimal test harness and a sample proxy configuration.
+This folder demonstrates a practical workflow for rapid model adoption and safe model switching using Plano (`plano`). It includes both a minimal test harness and a sample proxy configuration.
 
 ---
 
@@ -85,13 +85,13 @@ See `config.yaml` for a sample configuration mapping aliases to provider models.
    ```
 
 2. **Install dependencies:**
-  - Install all dependencies as described in the main Arch README ([link](https://github.com/katanemo/arch/?tab=readme-ov-file#prerequisites))
+  - Install all dependencies as described in the main Plano README ([link](https://github.com/katanemo/plano/?tab=readme-ov-file#prerequisites))
   - Then run
     ```sh
     uv sync
     ```
 
-3. **Start Arch Gateway**
+3. **Start Plano**
    ```sh
     run_demo.sh
    ```

demos/use_cases/model_choice_with_test_harness/bench.py

@@ -3,7 +3,7 @@ import json, time, yaml, statistics as stats
 from pydantic import BaseModel, ValidationError
 from openai import OpenAI
 
-# archgw endpoint (keys are handled by archgw)
+# Plano endpoint (keys are handled by Plano)
 client = OpenAI(base_url="http://localhost:12000/v1", api_key="n/a")
 MODELS = ["arch.summarize.v1", "arch.reason.v1"]
 FIXTURES = "evals_summarize.yaml"

demos/use_cases/model_choice_with_test_harness/pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "model-choice-newsletter-code-snippets"
 version = "0.1.0"
-description = "Benchmarking model alias routing with Arch Gateway."
+description = "Benchmarking model alias routing with Plano."
 authors = [{name = "Your Name", email = "your@email.com"}]
 license = {text = "Apache 2.0"}
 readme = "README.md"

demos/use_cases/model_choice_with_test_harness/run_demo.sh

@@ -17,18 +17,18 @@ start_demo() {
     echo ".env file created with API keys."
   fi
 
-  # Step 3: Start Arch
-  echo "Starting Arch with arch_config_with_aliases.yaml..."
+  # Step 3: Start Plano
+  echo "Starting Plano with arch_config_with_aliases.yaml..."
   planoai up arch_config_with_aliases.yaml
 
-  echo "\n\nArch started successfully."
+  echo "\n\nPlano started successfully."
   echo "Please run the following command to test the setup: python bench.py\n"
 }
 
 # Function to stop the demo
 stop_demo() {
-  # Step 2: Stop Arch
-  echo "Stopping Arch..."
+  # Step 2: Stop Plano
+  echo "Stopping Plano..."
   planoai down
 }