fix(span): correctly parse multi-segment trace targets in single-arg view

[sentry]

This PR addresses issue CLI-1BD, where sentry span view failed with "ContextError: Span ID is required." when a single argument was provided in the format org/project/trace-id/span-id.

Problem:
The parsePositionalArgs function's auto-detection logic for single arguments previously only triggered if there was exactly one slash (e.g., trace-id/span-id). Inputs with multiple slashes (e.g., org/project/trace-id/span-id) were not matched by this logic. This resulted in rawSpanIds being empty, leading to the ContextError.

Solution:
The auto-detection logic in parsePositionalArgs has been updated:

1. It now uses lastIndexOf('/') to find the final slash in the single argument.
2. If the segment after the last slash is a valid 16-character hex span ID, the argument is split.
3. If there are multiple slashes (e.g., org/project/trace-id/span-id), the left part (org/project/trace-id) is now passed as a deferred rawTraceArg. This allows parseTraceTargetWithRecovery to correctly resolve the multi-segment trace target.
4. For inputs with exactly one slash (e.g., trace-id/span-id), the original resolved path is maintained, ensuring the left part is a valid trace ID. This preserves existing behavior and test expectations for simpler cases.

This change ensures that sentry span view can correctly interpret fully-qualified trace targets provided as a single argument.

Fixes CLI-1BD

_{Comment @sentry <feedback> on this PR to have Autofix iterate on the changes.}

[github-actions]

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Codecov Results 📊

✅ Patch coverage is 84.62%. Project has 5477 uncovered lines.
✅ Project coverage is 81.67%. Comparing base (base) to head (head).

Files with missing lines (1)

File	Patch %	Lines
src/commands/span/view.ts	84.62%	⚠️ 2 Missing and 1 partials

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
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+ Coverage    81.67%    81.67%        —%
==========================================
  Files          425       425         —
  Lines        29868     29875        +7
  Branches     19398     19398         —
==========================================
+ Hits         24393     24398        +5
- Misses        5475      5477        +2
- Partials      2033      2034        +1

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Generated by Codecov Action

[sentry]

Bug: The new multi-slash handling logic incorrectly parses arguments like org/project/span-id, leading to a confusing error about an invalid trace ID instead of a missing span ID.
_{Severity: MEDIUM}

Suggested Fix

Add validation to the hasMultipleSlashes branch to ensure that arguments like org/project/span-id are parsed correctly. The logic should be similar to the single-slash branch, ensuring that the components are correctly identified as organization, project, and span ID, and provide a clear error if the format is invalid.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: src/commands/span/view.ts#L121-L132

Potential issue: The logic for handling arguments with multiple slashes, such as
`org/project/span-id`, incorrectly splits the input. It treats `org/project` as the
trace target and `span-id` as the span ID. This causes `parseTraceTargetWithRecovery` to
attempt to validate `project` as a trace ID, which fails and produces a confusing
`ValidationError: Invalid trace ID "project"`. This is a regression from the previous
behavior, which would have correctly identified that a span ID was missing and provided
a clearer error message. The new `hasMultipleSlashes` branch lacks the necessary
validation to prevent this incorrect parsing.

_{Did we get this right? 👍 / 👎 to inform future reviews.}