Add plain-language depression trial summary (#464)

[yehudalevy-collab]

Summary

Closes #464.

Adds an 823-word plain-language summary of the University of Arizona Open-LIFU depression trial for prospective participants, IRB members, and other non-specialist readers.

• Explains what the study tested, what researchers measured, and what they observed
• Reports the cohort, schedule, symptom trajectory, response, and remission numbers from the primary paper
• Separates observed improvement from causal or clinical claims
• States the small, open-label, uncontrolled design and short follow-up prominently
• Preserves the required regulatory disclaimer verbatim
• Links the peer-reviewed paper and ClinicalTrials.gov record

The issue refers to a wiki "Clinical Resources" section. The public wiki does not currently expose that structure, while the maintainer guidance and repository-based delivery used for #459 / #475 place the Markdown in this repository. I followed that live precedent with a root-level file and am happy to relocate it if maintainers prefer another path.

Clinical-framing notes

The paper is internally inconsistent about why two participants withdrew: the abstract says time constraints, while the Results and Discussion say lack of symptom improvement. The summary reports both accounts and retains the point on which the paper is consistent: withdrawal was not attributed to an adverse event.

The paper does not print exact group-average BDI-II values for weeks 1 and 3. The summary therefore reports the exact baseline mean and modeled change, describes the visible trajectory in Figure 3, and does not estimate follow-up means from the chart.

Clinician review remains required before merge, as specified in #464. After the English clinical wording is approved, I would also be glad to prepare a Spanish version if that would be useful.

Test plan

• Cross-check every numerical statement against Schachtner et al. (2025)

Summary statement	Primary-paper location	Source value
Cohort and age range	Abstract, Methods: Participants	20 enrolled; ages 18–50
Existing medication	Abstract; Table 1	50% reported current psychiatric medication use
Device and session schedule	Methods: Overview; Ultrasound session procedures	128-element array; 10 minutes per session; 5 sessions in week 1, then 3 per week for 2 weeks if needed; up to 11 sessions
Baseline BDI-II and trajectory	Table 1; Statistical analysis; Results; Figure 3	Mean 38.85 at baseline; modeled decrease 10.9 points per assessment-time step; largest visible decrease by week 1, followed by a smaller decrease through week 3
BDI-II response	Results: Depression symptoms and RNT	60% (12/20) met response criteria
HDRS response	Results: Depression symptoms and RNT	45% (9/20) met response criteria
Remission	Methods: Remission criteria; Results	35% (7/20) met BDI-II <13 and HDRS <8 thresholds
Study duration and withdrawals	Abstract; Results: Adverse events	Up to 3 weeks; 2/20 withdrew after week 1; no withdrawal attributed to an adverse event

• Confirm the regulatory disclaimer matches Plain-language summary of the depression trial outcomes (good first issue) #464 verbatim
• Confirm all abbreviations and specialist terms are defined on first use
• Confirm the 823-word document fits a five-minute read at approximately 165 words per minute
• Verify the DOI and ClinicalTrials.gov links resolve successfully
• Run pre-commit on depression_trial_summary.md (all applicable hooks pass, including Prettier and codespell)
• Obtain clinician review before merge