chore: 0.0.1a5 release

[patrick-chinchill]

Port fidelity release with 10 critical/high bug fixes.

[gemini-code-assist]

Code Review

This pull request increments the version to 0.0.1a5 and updates the changelog to reflect several critical and high-priority bug fixes across various platform adapters and core components. Review feedback identifies specific logic errors in the streaming markdown implementation regarding inline code and links, as well as a violation of the CommonMark specification in the heading parser's trailing hash stripping logic.

[gemini-code-assist]

The _remend implementation in streaming_markdown.py (referenced here) has several issues that affect its fidelity:

1. Inline Code Spans: It does not account for backticks (`). Markers like * or _ inside inline code are incorrectly counted for balancing, which leads to broken markdown when a stream contains literal markdown characters inside code spans.
2. Code Fence Mismatch: It always appends \n\``to close unclosed code fences, even if the fence was opened with~~~`.
3. Link Parentheses: It balances brackets [] for links but ignores the parentheses () for the URL part. A partially streamed link like [text](url will not be correctly closed.

The implementation should be updated to strip inline code content before counting markers and to track the specific fence character used.

[gemini-code-assist]

The trailing # stripping logic in markdown_parser.py (line 455) is implemented using .rstrip("#"). This is overly aggressive and will incorrectly strip meaningful characters from headings that legitimately end with a hash character, such as C# or F#. According to the CommonMark specification, a closing sequence of # characters must be preceded by a space to be considered a closing sequence. The implementation should be updated to respect this requirement.