Implement :from filter

[christian-schilling]

Change: from-filter

[Copilot]

Pull Request Overview

This PR adds two new filter operations, :from and :concat, to enable starting history filtering from a specific commit. The :from filter preserves original history up to a specified commit and applies filtering from that point onwards, while :concat is the underlying operation used internally.

Key changes:

• Added grammar rules for filter_from and filter_concat operations
• Implemented parsing logic and the HistoryConcat operation in the filter core
• Added test coverage for the new :from filter functionality

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
josh-core/src/filter/grammar.pest	Added grammar rules for filter_from and filter_concat
josh-core/src/filter/parse.rs	Implemented parsing logic for the new filter operations
josh-core/src/filter/mod.rs	Added HistoryConcat operation with support for lazy refs, spec generation, tree representation, and commit application
tests/filter/concat.t	Added test cases demonstrating :from filter behavior
tests/proxy/workspace_errors.t	Updated error message to include new filter types
docs/src/reference/filters.md	Added documentation for the new :from filter

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The filter_concat rule incorrectly uses \"from\" as the command keyword instead of \"concat\". This causes the parser to be unable to distinguish between :from() and :concat() operations. Change line 66 to use \"concat\".

[Copilot]

Missing separator between the reference and the filter spec. The format should be :concat({}{}) with a colon separator, similar to how Op::Rev and Op::Join format their output on lines 593 and 601. This should be format!(\"{}{}\", r.to_string(), spec(*filter)) to match the input format expected by the parser.

Suggested change

	format!(":concat({}{})", r.to_string(), spec(*filter))
	format!(":concat({}:{})", r.to_string(), spec(*filter))