feat(tools): collapse-consecutive-duplicates compression rule

adr-0003 §1.3 dedup: collapse runs of identical adjacent lines into `line (×N)`, order-preserving and lossless (count retained). Wired into ShellTool's default spec before HeadTail so the head/tail window holds distinct content. Safe as a default, unlike DropMatching.

infrastructure/tools/src/main/kotlin/com/correx/infrastructure/tools/shell/ShellTool.kt

@@ -2,6 +2,7 @@ package com.correx.infrastructure.tools.shell
 
 import com.correx.core.approvals.Tier
 import com.correx.core.events.events.ToolRequest
+import com.correx.core.tools.compression.CompressionRule.CollapseConsecutiveDuplicates
 import com.correx.core.tools.compression.CompressionRule.HeadTail
 import com.correx.core.tools.compression.CompressionRule.StripBlankLines
 import com.correx.core.tools.compression.DeclarativeCompressor
@@ -50,7 +51,14 @@ class ShellTool(
         setOf(ToolCapability.SHELL_EXEC, ToolCapability.PROCESS_SPAWN)
     override val paramRoles: Map<String, ParamRole> = mapOf("argv" to ParamRole.EXEC_COMMAND)
     override val outputCompressor: ToolOutputCompressor = DeclarativeCompressor(
-        OutputCompressionSpec(listOf(StripBlankLines, HeadTail(HEAD_LINES, TAIL_LINES)), bypassOnError = true),
+        OutputCompressionSpec(
+            // Collapse repeated identical lines (retries, warning spam) before truncating, so the
+            // head/tail window holds distinct content rather than duplicates. Dedup is lossless
+            // (count is preserved) and order-preserving, so it is safe as a default — unlike a
+            // progress-dropping regex, which can silently eat real output.
+            listOf(StripBlankLines, CollapseConsecutiveDuplicates, HeadTail(HEAD_LINES, TAIL_LINES)),
+            bypassOnError = true,
+        ),
     )
 
     override fun validateRequest(request: ToolRequest): ValidationResult {