fix: address the five alpha2 field reports

[HelloThisWorld]

Summary

Fixes the five issues reported from local v1.3.0-alpha2 testing. Four trace
back to the same area: alpha2 was the first release where the shell
integration module ran in a real terminal, and its emission had two defects
that cascaded into the Timeline and the progress bar.

#	Report	Root cause	Fix
1	\\\ before every prompt (\\\\ after a command)	The OSC terminator was written as '\\' — in PowerShell single quotes that is a literal two-character string, so every sequence ended ESC \ \ and the terminal printed the leftover backslash (3 = A, cwd, B; 4 = + D)	Get-WinTermOscSequence builds the terminator as '\', one character
2	Loaded command carried the prompt path	Marks were console side effects during prompt; the host writes those before the returned text, so 133;B landed before the visible prompt and the command region began at the prompt text	Invoke-WinTermPrompt returns one string with the marks embedded in FinalTerm order: D (2nd prompt on), A, cwd, prompt text, B
3	Progress bar animates at an idle prompt, without typing	ProgressStateMachine mapped CommandStart (133;B = composing input) to a visible indeterminate bar	133;B hides the shell snapshot; only 133;C (command executed) starts the running bar
4	Phantom Command text unavailable / Running row	The lifecycle model created an entry at 133;B	B is bookkeeping only (closes a previous never-completed command); the entry materializes at OutputStart/CommandFinished. The capability bit recorded at B still yields Running rather than Unknown
5	Rows jump on arrow keys / hover	_renderCommandTimeline rebuilt every ListView row on each selection change	A per-row content signature detects selection-only updates and moves SelectedIndex without rebuilding

Additionally, a module component blocked by antivirus at parse time (observed
for Compatibility.ps1 under some engines — including on the alpha2 test
machine, which showed a red parse error at session start) is now skipped
silently and recorded in diagnostics. Only functions that actually loaded are
exported, so a blocked component degrades that one capability and nothing
else; shell integration needs only the Private components.

Emission verified against a live session

The wrapped prompt now returns byte-exact FinalTerm order (captured from a
real import, ESC rendered):

first : <ESC>]133;A<ESC>\<ESC>]9;9;"D:\work\winTerm"<ESC>\PS D:\work\winTerm> <ESC>]133;B<ESC>\
second: <ESC>]133;D;0<ESC>\<ESC>]133;A<ESC>\<ESC>]9;9;"D:\work\winTerm"<ESC>\PS D:\work\winTerm> <ESC>]133;B<ESC>\

No stray characters, B after the prompt text, single-character terminators.

Test updates forced by the new semantics

• LifecycleUpdatesAreIncrementalAndIdempotent: 133;B alone asserts no
  entry (still idempotent); the entry materializes at OutputStart as
  Running.
• ActionLoadRejectsMissingCommandText: the entry-without-text scenario now
  uses an executed command with empty captured text.
• The no-output CopyOutput refusal now uses a bootstrapped mid-execution
  mark, since a B-only prompt no longer produces an entry.
• CommandCompletionClearsAtNextPrompt: asserts 133;B shows no bar (idle
  prompt quiet), 133;C shows Indeterminate, D→Success, prompt→hidden, and
  the next idle 133;B stays hidden.
• SplitOrDetachResetClearsReusableState: rehydration uses CommandExecuted.

Validation performed

Environment: Windows 11 Pro 26100, MSVC 14.44.35207, Windows SDK 10.0.26100.0.

Compiled tests — ran on fresh builds, passed

Suite	Result
SettingsModel winTerm classes	Total=44, Passed=44, Failed=0
CommandTimelineTests (Control)	Total=43, Passed=43, Failed=0

Builds — ran, clean: SettingsModel.UnitTests and Control.UnitTests
x64 Release both exit 0 (the latter includes Microsoft.Terminal.Control.Lib
with the TermControl change).

Live module check — ran: import on this machine (whose antivirus blocks
Compatibility.ps1) produces no console output, exports all six integration
functions, records the skipped component in diagnostics, and the prompt
emission is byte-exact as shown above.

Repository gates — ran, passed: verify-version.ps1,
verify-branding.ps1, test-release-workflow.ps1,
test-ci-classification.ps1, test-command-timeline.ps1,
test-visual-progress.ps1, test-privacy.ps1, test.ps1 -Suite Smoke.

Static — git diff --check clean; clang-format clean over changed ranges
(TermControl differences verified EOL-representation only).

Not run, with reason — test-shell-integration.ps1 -Shell All: this
machine's antivirus blocks Compatibility.ps1, so the compatibility-command
assertions cannot run locally (they now fail cleanly on the missing command
rather than a parse spill). The suite runs in the release workflow's gates on
clean runners, where alpha1 and alpha2 both passed it.

No screenshot was needed or created. winterm-site is untouched.

Checklist

• The change is focused and does not include unrelated formatting.
• Tests were added or updated where appropriate.
• All tests claimed above actually ran and passed.
• User-facing behavior and limitations are documented in this repository.
• This source/docs commit updates the root CHANGELOG.md.
• The Wiki Development-Changes.md ledger has been pushed with the final source SHA, link, summary, and checkpoint/release.
• Documentation screenshots reuse a suitable existing sanitized winterm-site asset, or no screenshot was added.
• Version or schema changes include compatibility and migration notes.
• Package identity, winterm.exe, and Microsoft Terminal coexistence remain isolated.
• No command text, terminal output, clipboard content, credentials, or private paths are logged.
• New source and script files contain the appropriate MIT license header.
• I did not include generated build output, secrets, certificates, or local absolute paths.

Source ↔ Wiki mapping

Source commit	Wiki commit	Wiki pages
09bd1b5	214dfca	Development-Changes

Boundary

No persistent history, no output cache, no output search, no heuristic prompt
detection, no telemetry. Workspace schema (2), docking model (1), shell
protocol (1), theme schema (1), update manifest schema (1), package identity,
and signing policy are unchanged. Version metadata is unchanged. No
winterm-site change.

Next step after this merges: prepare and publish v1.3.0-alpha3 for local
re-testing.