refactor: slim project to lean C++17 lab (Occam's razor)

Remove over-engineering for a hobby/learning project:

- Delete VitePress docs site (docs/, root package.json, 9632 lines),
  bilingual README (keep Chinese-only), and ADRs.
- Delete governance docs (CODE_OF_CONDUCT, SECURITY, CONTEXT,
  CONTRIBUTING) and .devcontainer/.
- Remove Streaming state-machine layer (encoder.hpp with
  State/Encoder/Decoder abstract classes, BufferEncoder/BufferDecoder
  wrappers). encode_buffer/decode_buffer now take a BufferTransform
  function pointer directly — algorithms never used the streaming
  interface.
- Prune StatusCode enum to used values (OK/ERR_CORRUPT/ERR_SIZE_LIMIT);
  drop unused INITIAL_DECODE_OVERHEAD constant.
- Merge CI into single ci.yml (remove ci-docs, codeql, docs-pages).
- Simplify issue/PR templates (drop Go/Rust/OpenSpec/streaming refs).

Binary format contract preserved (magic bytes, frequency table LE
layout, RLE pair layout, 4 GiB/1 GiB limits). 4 algorithms unchanged
(720 lines).

shared layer: 1183 -> 735 lines. Net: -16627 lines.

Verified: make test (36 CLI smoke + unit tests), make lint, 4-algo
round-trip.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: LessUp

.devcontainer/Dockerfile

@@ -13,14 +13,13 @@ Describe the failure in one or two sentences.
 ## Scope
 
 - Algorithm: Huffman / Arithmetic / Range Coder / RLE / Shared
-- Language: C++17 / Python scripts / Docs
-- Surface: CLI / library API / streaming API / conformance / docs / CI
+- Surface: CLI / library API / conformance / CI
 
 ## Reproduction
 
 ```bash
 # Paste the smallest command sequence that reproduces the issue.
-make test-conformance
+make test
 ```
 
 If the issue depends on an input file, include:

.devcontainer/devcontainer.json

@@ -1,6 +1,6 @@
 ---
 name: Feature request
-about: Propose a focused CompressKit algorithm, tooling, docs, or verification change
+about: Propose a focused CompressKit algorithm, tooling, or verification change
 title: "[FEATURE] "
 labels: enhancement
 assignees: ""
@@ -18,8 +18,7 @@ Describe the smallest useful change.
 ## Affected areas
 
 - Algorithm: Huffman / Arithmetic / Range Coder / RLE / Shared / N/A
-- Language: C++17 / Python scripts / Docs / CI
-- Contract impact: CLI / binary format / streaming API / conformance / none
+- Contract impact: CLI / binary format / conformance / none
 
 ## Verification plan
 

.github/ISSUE_TEMPLATE/bug_report.md

@@ -5,30 +5,25 @@ Explain what changed and why.
 ## Scope
 
 - [ ] Algorithm implementation
-- [ ] Shared streaming/buffer layer
-- [ ] Cross-language conformance
-- [ ] Documentation / Git Pages
+- [ ] Shared buffer layer
 - [ ] CI / repository tooling
-- [ ] OpenSpec
 
-Affected algorithms/languages:
+Affected algorithms:
 
 - Algorithm: Huffman / Arithmetic / Range Coder / RLE / Shared / N/A
-- Language: C++17 / Go / Rust / Python scripts / Docs / CI
 
 ## Compatibility
 
 - [ ] No binary format change
-- [ ] Binary format change, OpenSpec updated
-- [ ] Cross-language behavior changed, `make test-conformance` updated
+- [ ] Binary format change (requires design review)
 
 ## Verification
 
 Paste the commands run locally:
 
 ```bash
 make test
-npm run docs:build
+make lint
 ```
 
 ## Review focus
@@ -38,4 +33,3 @@ Call out anything reviewers should inspect closely, especially:
 - encoder/decoder pair compatibility
 - Range Coder large-file behavior
 - generated artifacts or ignored files
-- OpenSpec requirement alignment