M2.6: shorter wording for content in or after damage

Marking a figure decorative or a tag's content as an artifact refuses content that may be in a
damaged or unreadable content stream, or after the damage. The two errors now say so in one
clause, and that nothing was changed, which holds: both return before touching the document. The
mark-as-artifact tool's description names the case in a few words.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY

crates/a11y/src/alt.rs

@@ -25,9 +25,7 @@ pub enum AltError {
     NotAFigure(u32),
     #[error("the page has more content than can be edited")]
     TooLarge,
-    #[error(
-        "the figure's content is, or may be, in a content stream that is damaged partway or doesn't decode, or after the damage, where it can't be rewritten without losing or misreading what wasn't read"
-    )]
+    #[error("the figure's content may be in a damaged or unreadable content stream, or after the damage, so nothing was changed")]
     Damaged,
     #[error("{0}")]
     Cos(#[from] pdfcraft_cos::CosError),
@@ -56,9 +54,7 @@ pub enum ArtifactError {
     ParentTree(String),
     #[error("the page has more content than can be edited")]
     TooLarge,
-    #[error(
-        "the tag's marked content is, or may be, in a content stream that is damaged partway or doesn't decode, or after the damage, where it can't be rewritten without losing or misreading what wasn't read"
-    )]
+    #[error("the tag's marked content may be in a damaged or unreadable content stream, or after the damage, so nothing was changed")]
     Damaged,
     #[error(transparent)]
     Cos(#[from] pdfcraft_cos::CosError),

crates/automation/src/tools.rs

@@ -1285,7 +1285,7 @@ pub fn tools() -> Vec<ToolDef> {
                 "property": { "type": "string", "enum": ["type", "title", "actual_text", "alternate_text", "language", "summary", "scope"] },
                 "value": { "type": "string" },
             }), &["doc", "object", "generation", "property"])),
-        t("accessibility_mark_tag_artifact", "Mark tag content as artifact", "Mark a reachable leaf structure tag's direct marked content as an artifact and remove the tag from the reading structure. Use object and generation from accessibility_tags. Tags with child structure elements, no direct marked content, content not found on its page, or content that is, or may be, in a content stream damaged partway or that doesn't decode, or after the damage, are rejected. Undoable.")
+        t("accessibility_mark_tag_artifact", "Mark tag content as artifact", "Mark a reachable leaf structure tag's direct marked content as an artifact and remove the tag from the reading structure. Use object and generation from accessibility_tags. Tags with child structure elements, no direct marked content, content not found on its page, or content that may be in or after a damaged content stream are rejected. Undoable.")
             .with(schema(json!({
                 "doc": doc(), "object": { "type": "integer", "minimum": 1 },
                 "generation": { "type": "integer", "minimum": 0, "maximum": 65535 },